Blood and other measurements in diabetics
diabetes data frame has 442 rows and 3 columns.
These are the data used in the Efron et al "Least Angle Regression" paper.
The x matrix has been standardized to have unit L2 norm in each column and zero mean. The matrix x2 consists of x plus certain interactions.
Efron, Hastie, Johnstone and Tibshirani (2003) "Least Angle Regression" (with discussion) Annals of Statistics